Results for "Michael Volpp"

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Meta-Learning Acquisition Functions for Bayesian OptimizationApr 04 2019Apr 09 2019Many practical applications of machine learning require data-efficient black-box function optimization, e.g., to identify hyperparameters or process settings. However, readily available algorithms are typically designed to be universal optimizers and ... More
Trajectory-Based Off-Policy Deep Reinforcement LearningMay 14 2019Policy gradient methods are powerful reinforcement learning algorithms and have been demonstrated to solve many complex tasks. However, these methods are also data-inefficient, afflicted with high variance gradient estimates, and frequently get stuck ... More
Meta-Learning Acquisition Functions for Bayesian OptimizationApr 04 2019Many practical applications of machine learning require data-efficient black-box function optimization, e.g., to identify hyperparameters or process settings. However, readily available algorithms are typically designed to be universal optimizers and ... More
An algorithm for quantifying dependence in multivariate data setsJul 04 2012Sep 27 2012We describe an algorithm to quantify dependence in a multivariate data set. The algorithm is able to identify any linear and non-linear dependence in the data set by performing a hypothesis test for two variables being independent. As a result we obtain ... More
Logic Programming with Graph Automorphism: Integrating naut with Prolog (Tool Description)Jul 17 2016Aug 01 2016This paper presents the plnauty~library, a Prolog interface to the nauty graph-automorphism tool. Adding the capabilities of nauty to Prolog combines the strength of the "generate and prune" approach that is commonly used in logic programming and constraint ... More
Slow Steady-Shear of Plastic Bead RaftsOct 12 2004Experimental measurements of the response of a two dimensional system of plastic beads subjected to steady shear are reported. The beads float at the surface of a fluid substrate and are subjected to a slow, steady-shear in a Couette geometry. The flow ... More
Asymmetric response of a jammed plastic bead raftMay 18 2006Fluctuation-dissipation relations have received significant attention as a potential method for defining an effective temperature in nonequilibrium systems. The successful development of an effective temperature would be an important step in the application ... More
Examples of nonpolygonal limit shapes in i.i.d. first-passage percolation and infinite coexistence in spatial growth modelsSep 13 2010Mar 13 2013We construct an edge-weight distribution for i.i.d. first-passage percolation on $\mathbb{Z}^2$ whose limit shape is not a polygon and whose extreme points are arbitrarily dense in the boundary. Consequently, the associated Richardson-type growth model ... More
Interface dynamics in discrete forward-backward diffusion equationsApr 05 2013We study the motion of phase interfaces in a diffusive lattice equation with bistable nonlinearity and derive a free boundary problem with hysteresis to describe the macroscopic evolution in the parabolic scaling limit. The first part of the paper deals ... More
Group analysis of differential equations and generalized functionsDec 28 1999We present an extension of the methods of classical Lie group analysis of differential equations to equations involving generalized functions (in particular: distributions). A suitable framework for such a generalization is provided by Colombeau's theory ... More
What the characters of irreducible subrepresentations of Jordan cells can tell us about LCFTJul 22 2013Jan 04 2014In this article, we review some aspects of logarithmic conformal field theories which can be inferred from the characters of irreducible submodules of indecomposable modules. We will mainly consider the W(2,2p-1,2p-1,2p-1) series of triplet algebras and ... More
A Worst-case Bound for Topology Computation of Algebraic CurvesApr 08 2011Computing the topology of an algebraic plane curve $\mathcal{C}$ means to compute a combinatorial graph that is isotopic to $\mathcal{C}$ and thus represents its topology in $\mathbb{R}^2$. We prove that, for a polynomial of degree $n$ with coefficients ... More
Comparison between step strains and slow steady shear in a bubble raftDec 20 2004We report on a comparison between stress relaxations after an applied step strain and stress relaxations during slow, continuous strain in a bubble raft. A bubble raft serves as a model two-dimensional foam and consists of a single layer of bubbles on ... More
Evaluation of Contactless Smartcard AntennasJul 23 2015This report summarizes the results of our evaluation of antennas of contactless and dual interface smartcards and our ideas for user-switchable NFC antennas. We show how to disassemble smartcards with contactless capabilities in order to obtain the bare ... More
A Variant of K-theory: K_{+-}Feb 11 2003We describe a variant of K-theory for spaces with involution, built from vector bundles which are sent to their negative under the involution.
The periodic Floer homology of a Dehn twistOct 04 2004May 02 2005The periodic Floer homology of a surface symplectomorphism, defined by the first author and M. Thaddeus, is the homology of a chain complex which is generated by certain unions of periodic orbits, and whose differential counts certain embedded pseudoholomorphic ... More
The role of blood circulatory system in thermal regulation of animals explained by entropy production analysisAug 16 2013A novel model of thermal regulation of homoeothermic animals has been implemented. The model is based on a non-equilibrium thermodynamic approach which introduces entropy balance and the rate of entropy generation as a formulation of The Second Law. The ... More
Hysteresis and phase transitions in a lattice regularization of an ill-posed forward-backward diffusion equationOct 18 2016We consider a lattice regularization for an ill-posed diffusion equation with trilinear constitutive law and study the dynamics of phase interfaces in the parabolic scaling limit. Our main result guarantees for a certain class of single-interface initial ... More
Stopping Active Learning based on Predicted Change of F Measure for Text ClassificationJan 26 2019During active learning, an effective stopping method allows users to limit the number of annotations, which is cost effective. In this paper, a new stopping method called Predicted Change of F Measure will be introduced that attempts to provide the users ... More
A note on Neumann problems on graphsMar 22 2018We discuss Neumann problems for self-adjoint Laplacians on (possibly infinite) graphs. Under the assumption that the heat semigroup is ultracontractive we discuss the unique solvability for non-empty subgraphs with respect to the vertex boundary and provide ... More
Hysteresis and phase transitions in a lattice regularization of an ill-posed forward-backward diffusion equationOct 18 2016Aug 06 2017We consider a lattice regularization for an ill-posed diffusion equation with trilinear constitutive law and study the dynamics of phase interfaces in the parabolic scaling limit. Our main result guarantees for a certain class of single-interface initial ... More
CPT and Other Symmetries in String/M TheorySep 20 2004Feb 05 2005We initiate a search for non-perturbative consistency conditions in M theory. Some non-perturbative conditions are already known in Type I theories; we review these and search for others. We focus principally on possible anomalies in discrete symmetries. ... More
Linear programming methods for exponential dominationJan 19 2018For a graph $G,$ we consider $D \subset V(G)$ to be a porous exponential dominating set if $1 \le \sum_{d \in D}$ $\left( \tfrac{1}{2} \right)^{dist(d,v) -1}$ for every $v \in V(G),$ where $dist(d,v)$ denotes the length of the shortest $dv$ path. The ... More
Scaling of the diffraction measure of $k$-free integers near the originMar 30 2019Asymptotics are derived for the scaling of the total diffraction intensity for the set of $k$-free integers near the origin, which is a measure for the degree of patch fluctuations.
On exponential domination of the consecutive circulant graphDec 14 2017For a graph $G,$ we consider $D \subset V(G)$ to be a porous exponential dominating set if $1\le \sum_{d \in D}$ $\left( \frac{1}{2} \right)^{\text{dist}(d,v) -1}$ for every $v \in V(G),$ where dist$(d,v)$ denotes the length of the smallest $dv$ path. ... More
Von Neumann categories and extended $L^2$ cohomologyOct 26 1996Jan 20 1997In this paper we suggest a new general formalism for studying the invariants of polyhedra and manifolds comming from the theory of von Neumann algebras. First, we examine generality in which one may apply the construction of the extended abelian category, ... More
Constructing Optimal Authentication Codes with Perfect Multi-fold SecrecyDec 03 2009We establish a construction of optimal authentication codes achieving perfect multi-fold secrecy by means of combinatorial designs. This continues the author's work (ISIT 2009) and answers an open question posed therein. As an application, we present ... More
Properties of Stars in the Subaru Deep FieldOct 05 2005We investigate the properties of objects in the Subaru Deep Field (SDF), using public catalogs constructed from images in several optical passbands. Using a small subset of objects most likely to be stars, we construct a stellar locus in three-dimensional ... More
Metric properties of discrete time exclusion type processes in continuumApr 29 2009Oct 29 2009A new class of exclusion type processes acting in continuum with synchronous updating is introduced and studied. Ergodic averages of particle velocities are obtained and their connections to other statistical quantities, in particular to the particle ... More
On Raw Coding of Chaotic DynamicsMar 24 2006We study raw coding of trajectories of a chaotic dynamical system by sequences of elements from a finite alphabet and show that there is a fundamental constraint on differences between codes corresponding to different trajectories of the dynamical system. ... More
Asymptotically exact spectral estimates for left triangular matricesSep 08 2000For a family of $n*n$ left triangular matrices with binary entries we derive asymptotically exact (as $n\to\infty$) representation for the complete eigenvalues-eigenvectors problem. In particular we show that the dependence of all eigenvalues on $n$ is ... More
On self-similar sets with overlaps and inverse theorems for entropy in $\mathbb{R}^d$Mar 31 2015We study self-similar sets and measures on $\mathbb{R}^{d}$. Assuming that the defining iterated function system $\Phi$ does not preserve a proper affine subspace, we show that one of the following holds: (1) the dimension is equal to the trivial bound ... More
Non-Perturbative QED and QCD at Finite TemperatureSep 30 1998We present results of numerical solutions of Schwinger-Dyson equations for the finite-temperature quark and electron propagators. It is shown that both strongly coupled QED and QCD undergo a chiral symmetry restoring phase transition as the temperature ... More
Anisotropic Hydrodynamics: Three lecturesOct 20 2014Nov 03 2014Anisotropic hydrodynamics is a non-perturbative reorganization of relativistic hydrodynamics that takes into account the large momentum-space anisotropies generated in ultrarelativistic heavy-ion collisions. As a result, it allows one to extend the regime ... More
Heating of Intergalactic Gas and Cluster Scaling RelationsOct 14 1999X-ray observations of galaxy groups and clusters are inconsistent with the predictions of the simplest hierarchical clustering models, wherein non-baryonic and baryonic components are assembled together under the sole influence of gravity. These departures ... More
Chemical Composition of the Intracluster MediumOct 20 2003Clusters of galaxies are massive enough to be considered representative samples of the Universe, and to retain all of the heavy elements synthesized in their constituent stars. Since most of these metals reside in hot plasma, X-ray spectroscopy of clusters ... More
Dark Matter and Metal Abundances in Elliptical Galaxies from X-ray Observations of the Hot ISMAug 19 1998I review the results of recent analysis and interpretation of X-ray observations of elliptical galaxies, focusing on elemental abundances and dark matter. The hot ISM is characterized by subsolar Fe abundances and solar Si-to-Fe ratios; and, I compare ... More
Tidal disruption rate of stars by spinning supermassive black holesSep 28 2011Jan 25 2012A supermassive black hole can disrupt a star when its tidal field exceeds the star's self-gravity, and can directly capture stars that cross its event horizon. For black holes with mass M > 10^7 solar masses, tidal disruption of main-sequence stars occurs ... More
Transition from adiabatic inspiral to plunge into a spinning black holeJan 19 2011May 20 2011A test particle of mass mu on a bound geodesic of a Kerr black hole of mass M >> mu will slowly inspiral as gravitational radiation extracts energy and angular momentum from its orbit. This inspiral can be considered adiabatic when the orbital period ... More
Entanglement-enhanced spreading of correlationsJul 02 2015Dec 18 2015Starting from a product initial state, equal-time correlations in nonrelativistic quantum lattice models propagate within a lightcone-like causal region. The presence of entanglement in the initial state can modify this behavior, enhancing and accelerating ... More
Diverging equilibration times in long-range quantum spin modelsMar 04 2011Mar 30 2011The approach to equilibrium is studied for long-range quantum Ising models where the interaction strength decays like r^{-\alpha} at large distances r with an exponent $\alpha$ not exceeding the lattice dimension. For a large class of observables and ... More
Stationary points approach to thermodynamic phase transitionsOct 21 2010Nonanalyticities of thermodynamic functions are studied by adopting an approach based on stationary points of the potential energy. For finite systems, each stationary point is found to cause a nonanalyticity in the microcanonical entropy, and the functional ... More
Energy landscapes and their relation to thermodynamic phase transitionsDec 09 2008In order to better understand the occurrence of phase transitions, we adopt an approach based on the study of energy landscapes: The relation between stationary points of the potential energy landscape of a classical many-particle system and the analyticity ... More
Adapted coordinates in two dimensions and a proof of Puiseux's theoremJul 15 2008Sep 21 2008A method for finding Puiseux series goes back to Isaac Newton, which gives the terms of Puiseux series through an infinite recursive process; an additional argument is then used to show that the resulting Puiseux series are convergent. This paper provides ... More
Applications of an elementary resolution of singularities algorithm to exponential sums and congruences modulo p^nApr 25 2011Dec 10 2014We use the resolution of singularities algorithm of [G4] to provide new estimates for exponential sums as well as new bounds on how often a function f(x) such as a polynomial with integer coefficients is divisible by various powers of a prime p when x ... More
ExoticsFeb 04 2003We review lattice QCD results for glueballs (including a discussion of mixing with scalar mesons), hybrid mesons and other exotic states (such as $B_s B_s$ molecules).
Hadronic Physics from the LatticeOct 06 1997Topics covered in this review are the lattice gauge theory approach to the evaluation of non-perturbative hadronic interactions from first principles, particularly applications to glueballs, inter-quark potentials, the running coupling constant and hybrid ... More
Glueballs and Hybrid MesonsMay 07 1996The status of non-perturbative QCD calculations for mesons with gluonic excitation is presented. Lattice results for the glueball spectrum are reviewed. For hybrid mesons, the heavy quark results are summarised and new results are presented for light ... More
Hadronic Spectroscopy from the Lattice: Glueballs and Hybrid MesonsOct 20 1998Lattice QCD determinations appropriate to hadron spectroscopy are reviewed with emphasis on the glueball and hybrid meson states in the quenched approximation. Hybrids are discussed for heavy and for light quarks. The effects of sea quarks (unquenching) ... More
Hadronic Physics from the LatticeSep 27 1995Sep 28 1995We present the lattice gauge theory approach to evaluating non-perturbative hadronic interactions from first principles. We discuss applications to glueballs, inter-quark potentials, the running coupling constant, the light hadron spectrum and the pseudoscalar ... More
Quarkonia and Hybrids from the LatticeNov 03 1999The status of lattice determinations of quarkonia and hybrid meson spectra is presented and compared with experiment. Both quenched and unquenched results are discussed. Hybrid meson decays are considered.
Induced Gauge Theory on a Noncommutative SpaceApr 08 2008We discuss the calculation of the 1-loop effective action on four dimensional, canonically deformed Euclidean space. The theory under consideration is a scalar $\phi^4$ model with an additional oscillator potential. This model is known to be re normalisable. ... More
On a special property of tridiagonal matrices. Application to dual quasi-exactly solvable sextic potentials in quantum mechanicsFeb 17 2016We put forward and prove a simple theorem stating that the eigenvalues of a tridiagonal matrix change their sign (as a set), once the signs of the diagonal elements of the matrix are changed. We also provide an example of application of this theorem in ... More
Computing by Temporal Order: Asynchronous Cellular AutomataAug 14 2012Our concern is the behaviour of the elementary cellular automata with state set 0,1 over the cell set Z/nZ (one-dimensional finite wrap-around case), under all possible update rules (asynchronicity). Over the torus Z/nZ (n<= 11),we will see that the ECA ... More
Branching fractions and direct CP asymmetries of charmless decay modes at the TevatronDec 11 2006Mar 05 2007We present new CDF results on the branching fractions and time-integrated direct CP asymmetries for $B^{0}$ and $B^{0}_{s}$ decay modes into pairs of charmless charged hadrons (pion or kaon). The data set for this update amounts to 1 fb$^{-1}$ of $\bar{p}p$ ... More
Resolution of Syntactic Ambiguity: the Case of New SubjectsJun 20 1994Jun 20 1994I review evidence for the claim that syntactic ambiguities are resolved on the basis of the meaning of the competing analyses, not their structure. I identify a collection of ambiguities that do not yet have a meaning-based account and propose one which ... More
Invariants of closed braids via counting surfacesSep 06 2012Feb 27 2013A Gauss diagram is a simple, combinatorial way to present a link. It is known that any Vassiliev invariant may be obtained from a Gauss diagram formula that involves counting subdiagrams of certain combinatorial types. In this paper we present simple ... More
Coloring Link Diagrams And Conway-type Polynomial Of BraidsFeb 27 2013Oct 08 2013In this paper we define and present a simple combinatorial formula for a 3-variable Laurent polynomial invariant of conjugacy classes in Artin braid group $B_m$. We show that this Laurent polynomial satisfies the Conway skein relation and its coefficients ... More
Charged Higgs production in the flavored MSSMOct 22 2007In the Minimal Supersymmetric Standard Model squark mixing can significantly change the pattern of charged-Higgs production. We find that non-minimal flavor structures can have a sizeable impact on the charged-Higgs production cross section, whereas charged-Higgs ... More
Convective Ripening and Initiation of RainfallJul 23 2014This paper discusses the evolution of the droplet size distribution for a liquid-in-gas aerosol contained in a Rayleigh-B\'enard cell. It introduces a non-collisional model for broadening the droplet size distribution, termed 'convective ripening'. The ... More
How to account for quantum non-locality: ontic structural realism and the primitive ontology of quantum physicsAug 28 2014The paper has two aims: (1) it sets out to show that it is well motivated to seek for an account of quantum non-locality in the framework of ontic structural realism (OSR), which integrates the notions of holism and non-separability that have been employed ... More
Tidal Evolution of Asteroidal Binaries. Ruled by Viscosity. Ignorant of RigidityJun 30 2015Nov 20 2015The rate of tidal evolution of asteroidal binaries is defined by the dynamical Love numbers divided by quality factors. Common is the (often illegitimate) approximation of the dynamical Love numbers with their static counterparts. As the static Love numbers ... More
Space-Efficient Manifest ContractsOct 10 2014The standard algorithm for higher-order contract checking can lead to unbounded space consumption and can destroy tail recursion, altering a program's asymptotic space complexity. While space efficiency for gradual types---contracts mediating untyped ... More
Decoupling of the Kontsevich-Zorich cocycle modulo $q$ and uniform spectral gapSep 18 2016The purpose of this article is to show that technology recently developed by Bourgain, Gamburd and Sarnak (2011), Oh and Winter (2014) and Bourgain, Kontorovich and Magee (2015) to prove spectral gap results in the spirit of Selberg's `$3/16$ Theorem' ... More
Beamline Instrumentation for Future Parity-Violation ExperimentsOct 16 2014The parity-violating electron scattering community has made tremendous progress over the last twenty five years in their ability to measure tiny asymmetries of order 100 parts per billion (ppb) with beam-related corrections and systematic errors of a ... More
Alexandrov spaces with large volume growthMay 13 2014Let $(X,d)$ be an $n$-dimensional Alexandrov space whose Hausdorff measure $\mathcal{H}^n$ satisfies a condition giving the metric measure space $(X,d,\mathcal{H}^n)$ a notion of having nonnegative Ricci curvature. We examine the influence of large volume ... More
Volume growth and the topology of Gromov-Hausdorff limitsMar 29 2010We examine topological properties of pointed metric measure spaces $(Y, p)$ that can be realized as the pointed Gromov-Hausdorff limit of a sequence of complete, Riemannian manifolds $\{(M^n_i, p_i)\}_{i=1}^{\infty}$ with nonnegative Ricci curvature. ... More
Addendum to: On the rational approximation of the sum of the reciprocals of the Fermat numbersNov 24 2015As a corollary of the main result of our recent paper, {\em On the rational approximation of the sum of the reciprocals of the Fermat numbers} published in this same journal, we prove that for each integer $b\geq 2$ the irrationality exponent of $\sum_{n\geqslant ... More
Two-electron state from the Floquet scattering matrix perspectiveNov 03 2013Two single-particle sources coupled in series to a chiral electronic waveguide can serve as a probabilistic source of two-particle excitations with tunable properties. The second-order correlation function, characterizing the state of emitted electrons ... More
Floquet scattering matrix theory of heat fluctuations in dynamical quantum conductorsFeb 05 2014May 28 2014I present the Floquet scattering matrix theory of low-frequency heat fluctuations in driven multi-terminal quantum-coherent conductors in the linear response regime and beyond. The intrinsic fluctuations of energy of dynamically excited electrons are ... More
Floquet scattering matrix approach to the phase noise of a single-electron source in the adiabatic regimeMar 23 2013We give the basic elements of the Floquet scattering matrix approach to the dynamic quantum transport in mesoscopic and nanoscopic conductors. We use the scattering formalism to discuss the noise power spectrum of a single electron source working in the ... More
Challenges and Directions for Engineering Multi-agent SystemsSep 07 2012In this talk I review where we stand regarding the engineering of multi-agent systems. There is both good news and bad news. The good news is that over the past decade we've made considerable progress on techniques for engineering multi-agent systems: ... More
The Cosmic-Ray Positron and Electron Excess: An Experimentalist's Point of ViewMay 04 2009The recent report by the PAMELA team of the observed rise in the cosmic-ray positron fraction above a few GeV and the report of an excess of cosmic-ray electrons around a few hundred GeV by the ATIC collaboration has resulted in a flurry of publications ... More
A Neural Bayesian Estimator for Conditional Probability DensitiesFeb 18 2004This article describes a robust algorithm to estimate a conditional probability density f(t|x) as a non-parametric smooth regression function. It is based on a neural network and the Bayesian interpretation of the network output as a posteriori probabability. ... More
Floer homology of families IAug 12 2003Nov 06 2007In principle, Floer theory can be extended to define homotopy invariants of families of equivalent objects (e.g. Hamiltonian isotopic symplectomorphisms, 3-manifolds, Legendrian knots, etc.) parametrized by a smooth manifold B. The invariant of a family ... More
The extremal Secant Conjecture for curves of arbitrary gonalityDec 01 2015Dec 12 2015Let $C$ be a curve and $L$ a very ample line bundle. The Green-Lazarsfeld Secant conjecture predicts that if the degree of $L$ is at least $2g+p+1-2h^1(C,L)-Cliff(C)$ and if, in addition, $L$ is $p+1$ very ample, then the Koszul group $K_{p,2}(C,L)$ vanishes. ... More
Interactions and the Theta Term in One-Dimensional Gapped SystemsOct 28 2010Nov 02 2011We study how the \theta -term is affected by interactions in certain one-dimensional gapped systems that preserve charge-conjugation, parity, and time-reversal invariance. We exploit the relation between the chiral anomaly of a fermionic system and the ... More
The Impact of Disjunction on Reasoning under Existential Rules: Research SummaryMay 16 2014Datalog+/- is a Datalog-based language family enhanced with existential quantification in rule heads, equalities and negative constraints. Query answering over databases with respect to a Datalog+/- theory is generally undecidable, however several syntactic ... More
Interacting Many-Investor Models, Opinion Formation and Price Formation with Non-extensive StatisticsApr 11 2010Apr 13 2010We seek to utilize the nonextensive statistics to the microscopic modeling of the interacting many-investor dynamics that drive the price changes in a market. The statistics of price changes are known to be fit well by the Students-T and power-law distributions ... More
Exact Coupling Of Event Horizons In Curved Spacetime Heterostructures. Application To Black-Hole PhysicsMay 22 2010Recently we have discussed the generalized parametrized Klein-Gordon equation for curved spacetime. We have also discussed its derivation from several approaches, the direct Feynman parametrization, the state function entropy or equivalently the information ... More
Nonlinear Bloch-Torrey EquationMar 29 2010Recently, there has been an examination of the nonexponential relaxation profiles of the NMR signal. The exponential relaxation from Bloch-Torrey equations with constant diffusion coefficients are known to be an approximation, and research has been in ... More
The Impact of Galaxies on their Environment from Observations of Gravitationally lensed QSOsNov 01 2001Observations of absorption systems in close, multiple lines of sight to gravitationally lensed QSOs can be used to infer the density fluctuations and motions of the gas clouds giving rise to the Lyman alpha forest phenomenon and to QSO metal absorption ... More
Small Scale Structure in the Universe and the Distribution of Baryons at High RedshiftSep 14 1997We briefly discuss the relevance of Lyman alpha forest observations for measuring cosmological parameters, comparing the properties of high z QSO spectra with those of artifical spectra from hydrodynamic simulations, based on hierarchical cosmologies. ... More
Active Galaxies With Double-Peaked Emission Lines and What They Imply About the "Broad-Line Region"Oct 22 2003I review the distinguishing observational characteristics of active galaxies with double-peaked emission lines and their implications for the nature of the line-emitting region. Since double-peaked lines most likely originate in the outer parts of the ... More
Few nucleon dynamics in a nuclear mediumSep 01 1998Few body methods are used in many particle physics to describe correlations, bound states, and reactions in strongly correlated quantum systems. Although this has already been recognized earlier, rigorous attempts to treat three-body collisions have only ... More
Model Analysis of Time Reversal Symmetry Test in the Caltech Fe-57 Gamma-Transition ExperimentApr 13 1993The CALTECH gamma-transition experiment testing time reversal symmetry via the E2/M1 mulipole mixing ratio of the 122 keV gamma-line in Fe-57 has already been performed in 1977. Extending an earlier analysis in terms of an effective one-body potential, ... More
Large NNov 29 2008I review some of the things we have learned about large N gauge theories (and QCD at N=oo) from lattice calculations in recent years. I point to some open problems.
Next Challenges in Bringing Artificial Immune Systems to Production in Network SecurityMay 13 2008The human immune system protects the human body against various pathogens like e.g. biological viruses and bacteria. Artificial immune systems reuse the architecture, organization, and workflows of the human immune system for various problems in computer ... More
Probable member stars of the gravitational theory-testing globular clusters AM 1, Pal 3 and Pal 14Oct 24 2005Some of the Galactic outer halo globular clusters are excellent tools to probe gravitational theories in the regime of weak accelerations (Baumgardt et al. 2005). The measurement of the line-of-sight velocity dispersion among stars in these clusters will ... More
Is the new citation-rank approach P100' in bibliometrics really new?Sep 17 2014The percentile-based rating scale P100 describes the citation impact in terms of the distribution of unique citation values. This approach has recently been refined by considering also the frequency of papers with the same citation counts. Here I compare ... More
A Case Study of the Arbitrariness of the h-Index and the Highly-Cited-Publications IndicatorFeb 26 2013The arbitrariness of the h-index becomes evident, when one requires q*h instead of h citations as the threshold for the definition of the index, thus changing the size of the core of the most influential publications of a dataset. I analyze the citation ... More
Restricting the h-index to a citation time window: A case study of a timed Hirsch indexDec 09 2014The h-index has been shown to increase in many cases mostly because of citations to rather old publications. This inertia can be circumvented by restricting the evaluation to a citation time window. Here I report results of an empirical study analyzing ... More
How to improve the outcome of performance evaluations in terms of percentiles for citation frequencies of my papersAug 13 2014Using empirical data I demonstrate that the result of performance evaluations by percentiles can be drastically influenced by the proper choice of the journal in which a manuscript is published.
Empirical Evidence for the Relevance of Fractional Scoring in the Calculation of Percentile Rank ScoresJan 30 2013Fractional scoring has been proposed to avoid inconsistencies in the attribution of publications to percentile rank classes. Uncertainties and ambiguities in the evaluation of percentile ranks can be demonstrated most easily with small datasets. But for ... More
Tame distillation and desingularization by $p$-alterationsAug 25 2015We strengthen Gabber's $l'$-alteration theorem by avoiding all primes invertible on a scheme. In particular, we prove that any scheme $X$ of finite type over a quasi-excellent threefold can be desingularized by a $\mathrm{char}(X)$-alteration, i.e. an ... More
Reduced operator algebras of trace-preserving quantum automorphism groupsFeb 22 2012Dec 16 2012Let $B$ be a finite dimensional C$^\ast$-algebra equipped with its canonical trace induced by the regular representation of $B$ on itself. In this paper, we study various properties of the trace-preserving quantum automorphism group $\G$ of $B$. We prove ... More
Embedding the dual complex of hyper-rectangular partitionsJul 13 2012Mar 08 2013A rectangular partition is the partition of an (axis-aligned) rectangle into interior-disjoint rectangles. We ask whether a rectangular partition permits a "nice" drawing of its dual, that is, a straight-line embedding of it such that each dual vertex ... More
Three jet cross sections in photoproduction at HERAAug 04 1998We calculate three jet cross sections in photoproduction using exact matrix elements for the direct and resolved contributions. Numerical distributions are presented in a generic, irreducible set of variables that allows to disentangle the dynamics of ... More
Analytical solutions of pure-spinor superstring field theoryNov 21 2012Jul 08 2013We examine the possibility of constructing analytical solutions describing marginal deformations in the open superstring field theory that is based on the non-minimal pure-spinor formalism. It is found out that some methods used for constructing solutions ... More
Democratic Superstring Field Theory and its Gauge FixingJan 06 2011This work is my contribution to the proceedings of the conference "SFT2010 - the third international conference on string field theory and related topics" and it reflects my talk there, which described the democratic string field theory and its gauge ... More